Hello, thank you for reaching out to Microsoft Q&A.
Do you see the 'I forgot my PIN' option as shown in the screenshot?
Only the 'Change PIN' option will ask for your Old PIN; instead, select 'I forgot my PIN'.
Go to Start > Settings > Accounts > Sign-in Options > PIN (Windows Hello) > Select "I forgot my PIN" and follow the prompts to reset it. This process will not ask for your old PIN.